The present invention relates generally to inflatable support surface beds, and more specifically relates to inflatable support surface beds providing low air loss patient support, or providing other therapies, to a patient supported thereon.
Numerous types of inflatable patient support surfaces have been proposed to support patients. One generic configuration of such a support system in use today includes a plurality of transverse air bags extending across the width of the bed support surface. A plurality of such bags are arranged in parallel to form either a part, or the entirety, of the patient support surface. As is well known relative to such beds, a blower supplies air through a manifolding system to each of the air bags. This manifolding system includes a controller, such as a microprocessor controller, which operates a plurality of valves to control the air flow to sets of one or more of the air bags forming "zones" of the bed.
One therapy offered by such beds is low air loss patient support. In this configuration, at least some of the bags will include either small apertures, or will be formed in whole or in part of air permeable fabric, to provide a flow of air to dry the bag and/or cover surface to thereby reduce the risk to the patient of bed sores.
Another therapy offered in conventional beds is turning, or lateral rotation, of the patient. Dramatically different systems exist in the prior art for turning a patient with transverse air bags. For example, one conventional system deflates alternate single-celled air bags along the length of the patient to allow the patient to drop into recesses or cutouts in the other set of air bags, which remain fully inflated. Another, different, system utilize the deflation of cells in multi-celled cushions all along the length of one side of the patient to lower that side of the patient, and the corresponding inflation of cells all along the length of the other side of the patient to simultaneously raise that side of the patient. The different approaches of each of the systems may present disadvantages in certain situations, however. Both systems can offer less than optimal patient support over a long term in some applications.
Other therapies which are found in conventional acute care beds include pulsation and percussion. Pulsation, or alternating of contact (support) points, has long been utilized in an attempt to reduce patient tissue damage, such as decubitus ulcers. Examples of such alternating pressure surfaces include U.S. Pat. No. 2,998,817 to Armstrong, issued Sep. 5, 1961; and EPO Application No. 0-168-215 to Evans, published Jan. 15, 1986. Percussion therapy consists of a sharp impact of pressure, preferably only in the chest area of the patient, to assist in maintaining portions of the patients' body, typically the lungs, clear of pooled fluid. Conventional apparatus utilize a quick inflation of a cell beneath the patient to provide the impact. The frequency of the percussive therapy may be increased to provide vibratory therapy.
Notwithstanding what therapies are offered, a primary concern with an inflatable bed or support surface is patient comfort. Because patients may remain on these types of beds for extended periods of time, the ability to provide an optimally comfortable support surface is an important objective of any inflatable support assembly. This objective remains even when therapies such as those discussed above are offered.
Another objective of an inflatable support assembly will be to provide a system to maintain a patient properly positioned on the bed during normal situations. This may be of particular importance during rotational therapy. The prior art has only achieved this objective with a limited degree of success.
Accordingly, the present invention provides a new method and apparatus for supporting the patient on an inflatable support surface, and for providing optimal comfort and patient positioning, while having the further capacity, as desired, to provide a range of therapies such as, for example, low air loss support, rotation, varying support pressure ("relaxation"), percussion or vibration to the patient.